Rock Island Lake Dam dam
Rock Island Lake Dam
Rock Island Lake Dam, located in Sparta, New Jersey, was completed in 1940 and serves as a recreational resource in the area. This private earth dam stands at 19 feet tall and spans 500 feet in length, with a storage capacity of 61 acre-feet and a drainage area of 0.09 square miles. Despite its primary purpose being recreation, the dam is also state-regulated by the New Jersey Department of Environmental Protection, with regular inspections conducted to ensure its safety and compliance.
The dam's condition assessment is rated as poor, with a significant hazard potential, indicating the need for potential maintenance and risk management measures. The last inspection took place in November 2021, with a frequency of every 2 years. While the dam has not been modified in recent years, emergency action plans have been prepared in the past to address any potential risks or incidents. With its location in Sparta Township and proximity to the Sparta Glen-TR river or stream, Rock Island Lake Dam remains an important structure for both recreational and safety purposes in the region.
Overall, Rock Island Lake Dam stands as a significant earth dam in Sussex County, New Jersey, contributing to the local landscape and offering recreational opportunities for residents and visitors. As a state-regulated structure with a history dating back to the 1940s, the dam plays a crucial role in water resource management and public safety in the area. With ongoing inspections and assessments, efforts are being made to ensure the dam's continued functionality and compliance with regulatory standards, highlighting its importance for the community and the environment.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Rock Island Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Green Pond Brook At Picatinny Arsenal Nj | 2 cfs | → |
| Eb Paulins Kill Near Lafayette Nj | 10 cfs | → |
| Green Pd Bk Bl Picatinny Lk At Picatinny Ars Nj | 3 cfs | → |
| Musconetcong River At Outlet Of Lake Hopatcong Nj | 17 cfs | → |
| Pequannock R At Macopin Intake Dam Nj | 6 cfs | → |
| Pequest River At Huntsville Nj | 29 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Rock Island Lake Dam.
Boat launches
- Jefferson Lake Road Sussex County
- Dell Avenue 9, Netcong
- West Shore Drive Stillwater Township
- North Corporate Drive 2, Riverdale
- Greenwood Lake Turnpike Ringwood
- Lakeside Avenue Pompton Lakes
Track Rock Island Lake Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Rock Island Lake Dam
Where does the data for Rock Island Lake Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Significant hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Rock Island Lake Dam.